package com.dc.controller;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;



/**
 * Servlet implementation class RandomServlet
 */
@WebServlet("/RandomServlet")
public class RandomServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
    

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// 在内存中创建图象,width,height：控制图片的宽和高
				int width = 111, height = 45;
				BufferedImage image = new BufferedImage(width, height,
						BufferedImage.TYPE_INT_RGB);
				// 获取图形上下文
				Graphics g = image.getGraphics();
				// 生成随机类
				Random random = new Random();
				// 设定背景色
				g.setColor(getRandColor(200, 250));
				g.fillRect(0, 0, width, height);
				// 设定字体
				g.setFont(new Font("Times New Roman", Font.PLAIN, 20));
				// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
				g.setColor(getRandColor(160, 200));
				for (int i = 0; i < 155; i++) {
					int x = random.nextInt(width);
					int y = random.nextInt(height);
					int xl = random.nextInt(12);
					int yl = random.nextInt(12);
					g.drawLine(x, y, x + xl, y + yl);
				}
				// 取随机产生的认证码(6位数字)
				String sRand = "";
				for (int i = 0; i < 6; i++) {
					String rand = String.valueOf(random.nextInt(10));
					sRand += rand;
					// 将认证码显示到图象中
					g.setColor(new Color(20 + random.nextInt(110), 20 + random
							.nextInt(110), 20 + random.nextInt(110)));
					// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
					g.drawString(rand, 13 * i + 6, 30);//控制六个验证码数字在图中的位置
				}
				// 图象生效
				g.dispose();
				
				try {
					ImageIO.write(image, "JPEG", response.getOutputStream());
				} catch (Exception e) {
					System.out.println("验证码图片产生出现错误：" + e.toString());
				}
				//保存验证码到Session
				request.getSession().setAttribute("randStr", sRand);
				
			}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		this.doGet(request, response);
	}

	/*
	 * 给定范围获得随机颜色
	 */
	private Color getRandColor(int fc, int bc) {
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}

}
